Although a substantial number of gear oil additive concentrates are available in the marketplace, there exists a need for an additive to provide limited slip or enhanced positraction performance in a wide range of mineral and synthetic base gear oils. A most welcome contribution to the art would be the provision of an additive composition enabling present-day gear oil formulations to exhibit improved positraction performance in the GM limited slip axle chatter test (R-4A1-4), commonly referred to as the "big wheel, little wheel test".
Inasmuch as gear oils and manual transmission oils (collectively referred to hereinafter in the specification and in the claims as "gear oils") are subjected to prolonged usage in differentials and like devices, it is also important to prevent sludge deposition on critical mechanical surfaces.